122 MILK AND ITS HYGIENIC RELATIONS 



by the use of a ' foreign ' protein. The absorption of ' foreign ' 

 protein by animals fed on this material within a few days after 

 birth is considered later. Similar results involving certain points 

 which will be considered immediately, were also obtained by Much 

 and Romer and by Much and Happich. 



Famulener immunised pregnant goats to the red corpuscles 

 of the sheep, and showed that a passive immunity to sheep's 

 corpuscles was obtained by suckling. He also demonstrated the 

 presence of the immune substances in the colostrum, and found 

 that the content of these bodies was sometimes actually higher in 

 colostrum than in the blood of the mother. If the immunisation 

 of the mother was only commenced after parturition x no immunity 

 was conferred by suckling, although the immune substances could 

 be detected in the milk, but in smaller amounts than were found 

 in the colostrum in the first experiments. These experiments 

 also show that absorption takes place only in the early days 

 after birth. 



The amount of absorption which occurs as a result of suckling 

 is not an entirely simple matter. The antitoxin which is injected 

 into the mother is usually derived from an animal of a different 

 species. For example, tetanus antitoxin may be derived from the 

 horse and injected into the mother in the form of horse serum. 

 This horse serum, when injected into the mother, will evidently enter 

 the blood stream, and, except in the case of a mare, the question 

 arises whether it passes out in the milk attached to the protein 

 of the horse serum or not. The results so far obtained seem to show 

 that there is probably a transference of the immune properties from 

 the horse serum, which formed the vehicle for the supply of anti- 

 toxin in the mother's blood, to the protein of the species which was 

 injected. 



The amount absorbed by suckling appears to depend upon 

 whether the immune properties are attached to the ' foreign ' 

 protein or to the protein of the same species. This has been 

 demonstrated by the following experiment. 



Much and Romer injected tetanus antitoxin derived from a 

 horse, into a cow, before parturition. The calf was fed from birth 

 with the milk of its mother, the amount of antitoxin in the milk 

 being estimated, as also the amount in the calf's serum. It was 

 found that about -fa of the amount of antitoxin present in the 

 milk was absorbed by the calf. If, instead of allowing the calf to 

 suckle from an immunised mother, the same amount of antitoxin 

 which had been found to be present in the milk of the immunised 

 mother was mixed with the milk in the form of horse-antitoxin 

 and fed to the calf, the absorption which occurred amounted only 

 to ^Jtf (or ten times as little as in the former case) of the amount 



1 Several days are required for the production of immunity in the mother, 

 so that immune substances would not appear in the milk until some days 

 after the commencement of immunisation. 



